Influence of alkyl chain length of monocationic ionic liquids towards pharmacological activities

In this present work, to synthesis alkyl and aryl substituted monocationic ionic liquids (ILs) of 1–benzyl–3–octadecylimidazolium bromide (ILa), 1–benzyl–3–octadecylbenzimidazolium bromide (ILb), 1–benzyl–3–ethylbenzimidazolium bromide (ILc), 1–benzyl–3–ethylimidazolium bromide (ILd) and 1–benzylpyridinium bromide (ILe), the synthesized ILs are structurally characterized using various physico–chemical, analytical and spectral (FT–IR, 1H & 13C NMR, EI-MS) studies. The synthesized ILs of 1–benzyl–3–ethylbenzimidazolium bromide (ILc), 1–benzyl–3–ethylimidazolium bromide (ILd) and 1–benzylpyridinium bromide (ILe) exhibited significant in vitro biological and antioxidant activities. Furthermore, the synthesized ILs (ILa– ILe) were tested for their in vitro cytotoxicity against human leukemia cancer cell line K–562, human ovarian cancer cell line SK–OV–3, human prostate cancer cell line DU–145 and human non-tumor cell line (normal fetal lung fibroblasts, MRC-5) by SRB assay protocol. The results indicate that 1–benzyl–3–octadecylimidazolium bromide (ILa) and 1–benzyl–3–octadecylbenzimidazolium bromide (ILb) showed remarkable toxicity against cancer cells and low toxicity against healthy cell line. These facts open the possibility of designing new nontoxic ionic liquids that can be used as active pharmaceutical ingredients in the liquid form.